Saturated and intense, colors based on gems (think rubies, emeralds, sapphires, topaz) are unquestionably daring and dramatic. In decorating, their richness can make milder colors in a room seem dull and drab, so they work best matched with equally vibrant tones or set against neutrals, such as gray and black (consider keeping them away from pastels). Jewel tones can help play up a room's best qualities and minimize its flaws. For instance, a large, bright room that seems grand and imposing can become intimate with luscious emerald green on the walls. Jewel tones also help emphasize the coziness of a small space.

"Concentrated shades, like teal and ruby red, with reflective accents -- mercury glass, gilded frames -- make you feel enveloped by the color rather than imprisoned by a tiny room," says Jessica Becker, an interior designer in Providence, R.I.

Warm with a twist. "My favorite combination is bright emerald, chocolate brown, and off-white," says New York City designer Timothy Whealon. "Also great is a shocking peacock blue with white painted furniture."

Walls

Next to painting a room black, there's nothing more arresting than covering walls in a jewel tone -- it electrifies a space. But remember: The sheen dramatically affects the color. "A matte finish will take the edge out of a jewel tone and make it look dark and dry," says Washington, D.C., interior decorator Annie Elliott. On the other end of the spectrum, semigloss can look too "nightclub." To preserve the vibrancy without going overboard, stay in the middle with an eggshell finish.

No-fail paint picks

With jewel-tone walls, white ceiling paint will give you a stark contrast. A warm neutral, like light gray or beige, will feel softer and more luxurious. Here, a few gems courtesy of Annie Elliott.

Peacock blue: "It has a tinge of mid-century nostalgia. Don Draper's sofa could be this color."

Emerald: "Use it in a dining room. It will look friendly during the day and mysterious at night."

Furniture

With large jewel-tone pieces, think texture. Rich colors have even more impact in reflective fabrics, such as velvet and silk. Dark jewel tones are also fantastic in leather -- and a playful departure from traditional brown.

Metal cabinet: Use it in the home office to stash supplies or in a playroom to hide toys.

Velvet chair: Try two in an entryway, on either side of a modern console.

Curvy chaise: A bedroom piece for lounging a la Mae West.

Acrylic nightstand: For a corner in the bathroom. Roll hand towels and tuck them inside

Accessories

Small jewel-tone accents are like a shot of B12 for a room. Since they're so vibrant, stick to solid colors rather than patterns, which can look garish. Group variations of one color, or experiment with combinations, treating the room "like a crown with many jewels rather than a solitaire ring," advises Elliott.

Tall bottles: Pretty in a sunny bathroom window -- or on a holiday buffet, near votives.